As it is shown in FIG. 2 illustrating a partial cross section of interconnects of a semiconductor device, interconnects of semiconductor devices are known to be produced by forming a Ta metal film 3 as a diffusion inhibiting film on the surface of a substrate 1 (hereafter referred to as a substrate) coated with an insulation film such as SiO2 having grooves 2 on its surfaces, forming a seed film 4 composed of pure copper on the surface of the Ta metal film 3, and forming a interconnects thin film 5 on the surface of the pure copper seed film 4 through plating or the like.
Metallic Ta used in the above-described Ta metal film 3 which is known as the diffusion inhibiting film is itself an expensive material. Therefore, development of inexpensive metal films acting as diffusion inhibiting films have been studied as alternatives to the Ta metal film. As an example of recent studies, FIG. 1 illustrates a partial cross section of the interconnects of a semiconductor device, where, by sputtering a CuMn copper alloy target, a Mn-containing copper alloy film is directly formed on the surface of the substrate 1 coated with an insulation film such as SiO2 having grooves 2 on its surface, and the thus formed Mn-containing copper alloy film is subsequently subjected to a heat treatment. Mn contained in the Mn-containing copper alloy film 7 reacts with the insulation film such as SiO2 on the substrate 1 and forms a layer 6 that contains complex oxides of Mn and Si. Since the Mn—Si complex oxide-containing layer 6 acts as a diffusion inhibiting film, formation of the expensive Ta metal film can be avoided. In addition, the Mn-containing copper alloy film 7 can be used as a seed film. Based on the above-described findings, extensive studies have been carried out with respect to the Mn-containing copper alloy film and the Mn—Si complex oxide-containing layer (Non Patent References 1, 2).
Non Patent Reference 1: Home Page of Semiconductor Technology Academic Research Center (STARC), June 8, Hei 17 (2005).
Non Patent Reference 2: Abstract of presentation on IITC, Jun. 8, 2005.